A research team within the U.S. Army Corps of Engineers recently 3-D printed full-scale concrete walls in an effort to create quick-to-assemble barracks for field housing, according to Engineering News Record. The project, named Automated Construction of Expeditionary Structures (ACES), aims to engineer structurally efficient and safe concrete barracks with precast roofs and 3-D-printed walls. In their latest tests, they were able to produce 9.5-foot-tall reinforced concrete walls for 32-foot by 16-foot barracks, made from about 25 cubic yards of concrete. The next phase of the testing will tackle printing concrete roof beams. Backed by the U.S. Marine Corps, Caterpillar Inc., NASA’s Marshall Space Flight Center, and the Kennedy Space Center, ACES is pushing the boundaries of military on-site construction using as little money and manpower as possible. The project has undergone two years of testing with structural engineering experts from the Chicago office of Skidmore, Owings & Merrill, who had previous experience working in 3-D printing through a project with the U.S. Department of Energy. After several iterations, the group concluded that construction time on such structures could shrink to a single day as opposed to five days, the average amount of time it takes to build wood-framed barracks. Printing concrete barracks would also eliminate the need to ship construction materials for conventional barracks by instead using local concrete from wherever the build-out would occur. For this prototype, ACES spent $6,000 and in addition, found out that it would take just three trained crew members per shift for three continuous printing sessions to build the barracks. Though exhausting, the process is even less labor intensive than basic barrack construction. While 3-D-printed building technology is looking more viable every day, it's not perfect yet. According to ENR, SOM said that pre-testing the performance of the concrete is imperative and that the printing process must not be interrupted to ensure overall structural efficiency. Cracks from shrinkage can occur on long, straight walls as well, so ACES employed a chevron design that undulates, changing direction every two feet. ACES will do further testing over the next month to refine the technology and the construction process. They expect to be done with the project's precast concrete roof in September and will then issue a report with design guidelines. During 2019, the group hopes to build four or five pilot machines for Marine Corps units to use in the field for additional evaluation.
Posts tagged with "Army Corps of Engineers":
The shores of New York and New Jersey are, as Hurricane Sandy demonstrated in 2012, particularly vulnerable to flooding, sea level rise, and extreme weather events. Coastal construction has become more resilient (though some question to what end) and flood prevention ideas both big and small have been floated to protect the area’s shores. Now, the U.S. Army Corps of Engineers has proposed several different approaches to preventing flood surges using gates and berms in and around New York Harbor, and environmentalists are sounding the alarm. The proposals are part of the New York-New Jersey Harbor and Tributaries Coastal Storm Risk Management Feasibility Study, a 2,150-mile survey of the region’s most vulnerable areas. The Corps has put together five schemes—four that use storm barriers, and one “as is” projection—and is soliciting feedback from New York and New Jersey residents with a series of information sessions this week. In designing floodwalls for New York Harbor or the Hudson and East Rivers, the Corps will need to balance ecological concerns with property protection; nonprofit clean water advocacy group Riverkeeper has called the Corps “hard infrastructure” solutions, those that use concrete barriers, detrimental to the health of the harbor and its waterways. The Hudson River is technically a tidal estuary and not a full-fledged river. Salt water from New York Harbor, and in turn the Atlantic Ocean, flows back up through the Hudson and mixes with fresh water from tributaries upstate to create a nutrient-rich environment. If the Corps's plan to install a five-mile-long gate across the harbor’s mouth between Sandy Hook, New Jersey, and Breezy Point in the Rockaways came to pass, Riverkeeper argues that the barrier would slowly cut off nutrients from the harbor and prevent contaminants from washing out into the ocean. “From Day One, these offshore barriers would start to restrict the tidal flow, contaminant and sediment transport, and migration of fish. They would impede the tidal ‘respiration’ of the river. We fear that a slow death would be inflicted on the river and that in time, the barriers would slowly, but surely, strangle the life out of the river as we know it.” The Corps alternative plans include: building berms, dunes, and seawalls across the lower-lying sections of the New York-New Jersey waterfront, with small floodgates across a few waterways; a barrier across the Staten Island-Brooklyn gap spanned by the Verrazzano-Narrows bridge and gates along Jamaica Bay; and targeted berms and seawalls across targeted low-lying coastal areas without any gates. Creating a centralized approach to flood prevention could be more effective than the piece-by-piece method currently being enacted but comes with its own set of risks. If a massive gate were installed to prevent flooding, it would need to be closed more and more frequently as sea levels rise and would increasingly cut off New York and New Jersey’s waterways from the ocean. Planning for a storm that currently has a probability of occurring once every hundred years may be futile as storms of such intensity become increasingly common. Seawalls have been linked to increased erosion, and if water builds up behind the wall, it can be hard to fully drain the affected area. The Corps is looking to identify a scheme to move forward with by the middle of this summer. However, with a possible price tag of $20 billion and several years of construction likely, whether or not the Corps can follow through is unclear. Interested New York and New Jersey residents can learn more at the following information sessions: Monday, July 9th, 3-5 PM and 6-8 PM at the Borough of Manhattan Community College in Tribeca, Richard Harris Terrace (main floor) 199 Chambers St, New York, NY 10007 Tuesday, July 10th, 3-5 PM and 6-8 PM at Rutgers University-Newark Campus, PR Campus Center, 2nd Floor, Essex Room 350 Martin Luther King Jr. Boulevard, Newark, NJ 07102 Wednesday, July 11th, 6-8 PM at the Hudson Valley Community Center in Poughkeepsie, Auditorium Room 110 South Grand Avenue, Poughkeepsie, NY 12603
Taking the podium at Pier 6 in Brooklyn Bridge Park, New York City Representative Nydia M. Velázquez introduced new legislation, called the "Waterfront of Tomorrow Act," to protect and fortify New York City's 538-miles of coastline. The bill would instruct the Army Corps of Engineers to come up with an in-depth plan to stimulate economic growth and job creation, update the ports, and implement flood protection measures. Sandwiched between Red Hook Container Terminal and One Brooklyn Bridge Park, a large residential development, the pier was an appropriate place for the Congresswoman to announce legislation that addresses the city's needs to bolster its shipping industry while also taking steps to mitigate flooding and ensure the resiliency and sustainability of its residential neighborhoods, parkland, and businesses. "I think the part [of the bill] that was the most exciting was about protecting New York City from future floods, and most importantly talked about hard and soft solutions. Different parts of NYC will need different solutions," said Rick Bell, Executive Director for AIA New York Chapter Center for Architecture. "This whole announcement talked about multifaceted approach." The bill is divided into four sections that propose flood protection and resiliency measures, a national freight policy, and "Green Port" designations and a grant program to promote the environmental sustainability of the shipping ports. The Army Corps of Engineers, in collaboration with the National Oceanographic and Atmospheric Administration, will be charged with coming up with a strategy to protect the waterfront from severe weather patterns and rising tides, including tide gates, oyster reef restoration, and wetland restoration. "Whether it is commerce, recreation, transportation, or our local environment, New Yorkers' lives are inextricably linked to the water that surrounds us," Velázquez said at the announcement. "Investing in our ports, coasts and waterfronts can improve our City and local communities." The timing of this bill is up in the air, but it will likely enter the conversation in September when Congress returns from the August District Work Period to discuss new legislation aimed at enhancing the nation's waterways.